PreSonus Studio Channel - Manual (Page 22)

OPERATION
20 | PreSonus 2007
3.3 EQUALIZERS
The equalizer in the Studio Channel is like a Swiss Army pocket knife, with the ability to carve out unwanted
frequencies as well as tailor your tone to enhance your sound. The custom-designed amplifiers in the EQ deliver
sweet-sounding gain/cut for ultra smooth highs, deep solid lows and clear midrange. The mid-band of the EQ
section has variable Q for controlling the width around the center point of the selected frequency. High and low
frequency bands give you the option for selecting peak/dip or shelving frequencies. What follows is a brief
explanation of how an EQ functions as well as some charts to help you navigate the frequency range of various
instruments to assist you in quickly setting the best EQ for your recordings and to help you get the most out of
your Studio Channel.
3.3.1 What is an EQ?
An equalizer is a device that allows you to adjust the volume of a frequency or range or frequencies within an
audio signal. In its simplest form, an EQ will let you turn the treble and bass up or down, allowing you to
adjust the coloration of, let’s say, your car stereo or an iPod. In recording, equalization is a high art. Good
equalization is critical to a good mix. When used correctly, an equalizer can provide the impression of
nearness or distance. It can also provide separation between similar sounds in a mix allowing them to both
shine through the mix.
The Parametric EQ
The Parametric EQ and semi-Parametric EQ are the most common equalizers found in most recording and
live situations because they offer continuous control over all parameters. The Parametric EQ divides the
audio signal’s frequency range in bands, usually three to seven, and provides the same set of control
parameters for each band: gain, frequency width (Q), and the center frequency of that Q.
The Q
The Q is by far the most useful tool a Parametric EQ offers. By adjusting the width of the Q you can
attenuate or boost a very narrow or broad range of frequencies. Each has its benefits, let’s look at the
narrow Q first.
A narrow Q has obvious attenuation benefits for removing unpleasant tones. Let’s say the snare drum in your
mix has an annoying ring to it. With a narrow Q, you can single this one frequency out (usually around 1
kHz) and remove it. This is also known as a “notch” filter. By notching out the offending frequency, you can
remove the problem without removing the instrument from the mix. A narrow Q is also useful in boosting
pleasant tones of an instrument such as the attack. Take for instance, a kick drum. A kick drum resonates
somewhere between 60-125 Hz, but the attack of the kick drum is much higher at around 2-5 kHz. By
setting a narrow Q and boosting the attack a bit, you can achieve a punchier kick drum without overpowering
the rest of the mix.
A broad Q accentuates or attenuates a larger band of frequencies. The broad Q and narrow Q are usually
used in conjunction with one another to achieve the desired effect. Let’s look at our kick drum again. We
have a kick drum that has a great big low end sound somewhere centered around 100 Hz and an attack
hitting in almost dead on at 4 kHz. In this example, you would use a broad Q boosted in the low frequency
band centered at 100Hz and a narrow Q boosted at 4 kHz. In this way you are accentuating the best and
downplaying everything else this particular kick drum has to offer.